The present invention relates to an editing area setting method and an editing area setting apparatus in an image forming apparatus which is capable of setting a synthetic area comprising a plurality of rectangular areas, as an editing area.
For the purpose of forming an image within a part of an original document (hereafter called trimming) or of forming an image within a section excluding a part of an original document (hereafter called masking) in an image forming apparatus such as an electrophotographic copying apparatus, there has conventionally been provided an image forming apparatus which is given an editing function.
In such an image forming apparatus as above, the following three methods are proposed for setting an area to accomplish trimming and masking: (A) a method wherein an area to be edited is limited to a rectangular area only and one rectangular area to be edited is set by inputting co-ordinates of only diagonal points of the rectangular area, (B) a method wherein an arbitrary polygonal area is used without limiting an area to be edited to a rectangular area and the polygonal area to be edited is set by sequentially inputting co-ordinates of every vertex thereof (Unexamined Japanese Patent Publication No.213168/1985), and (C) a method wherein at least four points of an image area are inputted and at least one outside area or one inside area is specified so that it is made possible to perform either of partial deletion, partial insertion, and circumferential deletion of the specified area (Unexamined Japanese Patent Publication No.3179/1986).
In the editing area setting method of the above (A), an area is set by inputting the co-ordinates of only diagonal points of a rectangular area, but with this method it is only possible to edit an area with respect to one rectangular area and there exists a problem that it is totally impossible to set an area of a shape other than rectangular. Particularly, it was entirely impossible to set a rectangular masking area inside of a rectangular area to be trimmed or to set a rectangular trimming area inside of a rectangular area to be masked.
Further in the editing area setting method of the above (B), because the co-ordinates corresponding to every vertex of a polygonal area must be inputted, there exists a problem that the co-ordinate inputting operation becomes complicated. Especially, even in case where it is sufficient to input the co-ordinates of a diagonal point to set a rectangular area, co-ordinates of four points must be inputted.
Furthermore, in the editing area setting method of the above (C), there exists problems that the coordinates of at least four points must be inputted, that it is necessary to input the co-ordinate of the point which corresponds to the outside or inside of the set area, and that the co-ordinate inputting operation becomes further complicated.